Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

The magazine reports in its latest issue hitting newsstands Tuesday that Sharper Image’s Ionic Breeze Quadra Silent Air Purifier and four other similar machines fail to significantly clean the air — but also release potentially unhealthy levels of ozone.

The article is being published two months after San Francisco-based Sharper Image agreed to pay the magazine’s publisher, Consumers Union, $525,000 in legal costs after a judge dismissed its libel suit. The failed lawsuit alleged that earlier magazine articles highly critical of the Ionic Breeze’s ability to reduce airborne particles were false and malicious.

2 million sold
Company lawyer E. Robert Wallach said Sharper Image was evaluating how to respond to the article, which advised against buying the machines. More than 2 million of the $350 units have been sold.

“It is astonishing that Consumers Union would continue its misguided efforts to attack the judgment and experience of millions of Americans who are satisfied with the performance of the Ionic Breeze products,” Wallach said in a statement.

In a statement of its own, Consumer Reports said the magazine’s latest article is accurate and that the nonprofit organization had called on federal regulators to look at the advertising claims being made by sellers of the five air purifiers it examined.

“All of these ’not recommended’ products did a poor job in our tests of removing dust, smoke and pollen from the air,” the statement said. “In addition, all five of these products failed in Consumer Reports’ labs the standard industry test for ozone generation.”

Consumers Union is based in Yonkers, N.Y.

Shares of Sharper Image Corp. fell 4 percent, or 67 cents, to close at $15.68 Monday on the Nasdaq Stock Market, near their 52-week low of $14.08.